Chemokines represent a superfamily of about 30 chemotactic cytokines acting as vital initiators and promulgators of inflammatory reactions. They range from 8 to 11 kD in molecular weight, are active over a 1 to 100 ng/mL concentration range, and are produced by a wide variety of cell types.
Interleukin 8 (IL-8), formerly called monocyte-derived neutrophil chemotactic factor (MDNCF) or neutrophil attractant/activation protein-1 (NAP-1), is a chemokine and a member of the cytokine family that displays chemotactic activity for specific types of leukocytes. IL-8 is a member of the CXC chemokine family in which an amino acid is present between the first two of four highly conserved cysteine residues. IL-8 is a polypeptide of which two predominant forms consist of 72 amino acids and 77 amino acids. Monocytes, macrophages, neutrophils, lymphocytes, dermal fibroblasts, keratinocytes, vascular endothelial cells, melanocytes, hepatocytes, and various tumor cell lines produce IL-8. IL-8 is a potent neutrophil chemokine and participates in the migration of neutrophils towards inflammatory sites. Upon binding to its high-affinity receptors (CXCR1 and CXCR2) which are present on the surface of neutrophils, IL-8 activates neutrophils by accelerating degranulation and elevating the free Ca2+ concentration in the cytoplasm and also induces neutrophil migration to thereby destroy the infiltrated tissue.
Although the neutrophil inflammatory response is essential for the destruction of bacteria which are invading the body, inappropriate neutrophil activation can cause a number of inflammatory disorders. For example, IL-8 has been recovered from inflammatory sites such as, pustulosis palmoplantaris (PPP) lesions, psoriatic scales, synovial fluid of patients with rheumatoid arthritis (RA), pleural fluid from empyema patients, alveolar macrophages from lungs with idiopathic pulmonary fibrosis, bronchioalveolar lavage fluids from patients with adult respiratory distress syndrome, cystic fibrosis, chronic bronchitis, and bronchiectasis. IL-8 is also associated with sepsis, asthma, glomerulonephritis, inflammatory bowel disease (IBD), ischaemia-reperfusion injury and multiple myeloma. Such conditions are characterized by inflammation accompanied by neutrophil infiltration and tissue damage.
IL-8 is also known to promote angiogenesis and, thus, growth of tumors. Such activity has been associated with the ELR motif within the IL-8 sequence. Human tumor cell lines such as, thyroid carcinoma, transitional cell carcinoma, trichilemmona, squamous cell carcinoma, and melanoma constitutively express IL-8 which plays a role in tumor invasion and metastasis.
Accordingly, antibodies specific for IL-8 are therapeutically important for treating diseases mediated by IL-8 activity. A hybridoma producing a human antibody against human IL-8, referred to as 2C6, has been described previously (U.S. Pat. No. 6,300,129 by Lonberg and Kay). However, additional antibodies specific for IL-8 are still needed.